[19:11:11] [Server thread/ERROR]: Could not pass event CraftItemEvent to DuelMe v0.17.4
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at net.minecraft.server.v1_11_R1.PlayerConnection.a(PlayerConnection.java:1839) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at net.minecraft.server.v1_11_R1.PacketPlayInWindowClick.a(SourceFile:33) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at net.minecraft.server.v1_11_R1.PacketPlayInWindowClick.a(SourceFile:10) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at net.minecraft.server.v1_11_R1.PlayerConnectionUtils$1.run(SourceFile:13) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_111]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_111]
at net.minecraft.server.v1_11_R1.SystemUtils.a(SourceFile:46) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at net.minecraft.server.v1_11_R1.MinecraftServer.D(MinecraftServer.java:739) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at net.minecraft.server.v1_11_R1.DedicatedServer.D(DedicatedServer.java:399) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at net.minecraft.server.v1_11_R1.MinecraftServer.C(MinecraftServer.java:675) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:574) [spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_111]
Caused by: java.lang.NullPointerException
at com.github.teozfrank.duelme.menus.AcceptMenu.onInventoryClick(AcceptMenu.java:75) ~[?:?]
at sun.reflect.GeneratedMethodAccessor448.invoke(Unknown Source) ~[?:?]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_111]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_111]
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[spigot-1.11.2-R0.1-SNAPSHOT.jar:git-Spigot-7d78b81-775f1e1]
... 15 more